This project will study the emergence of sexual problem behaviors in children who are at increased risk for disruptive behavior/conduct disorders. It will utilize a unique opportunity by adding a study on the development of sexual problem behaviors to a longitudinal project on determinants of disruptive behavior/conduct disorders, to be conducted in 100 boys aged 6, 7, and 8 years at study entry. The study participants are the younger brothers of juvenile delinquents adjudicated in New York Family Court because of personal or property offenses. The first goal of this project is the development of methods for the study of childhood sexual problem behaviors. A second goal is to identify predictors of sexual problem behaviors, and to explore whether or not they are also those that predict disruptive behavior/conduct disorders. Some descriptive information on AIDS-related knowledge, attitudes, and experiences will also be obtained. The ultimate goal is the development of programs to prevent sexual problem behaviors of childhood and early adolescence.